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2006 chevy trailblazer_ls
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Discussion Starter · #1 · (Edited)
Hello,
I have a 2006, 6cyl, 4X4, Trailblazer LS. Last winter I noticed that my 4 wheel drive had stopped working, since then I have replaced the splined disconnect and the actuator attached to the passenger side of the oil pan. I am now able to engage 4 wheel high and the automatic option (which switches the front wheels off and on as needed). I am unable to get it to go into 4 wheel low and when I make sharp turns (with 4 wheel drive engaged) going both forward and backward there is a loud grinding noise which seems to be coming from the drivers side off the front differential. Does anyone have any idea what may be causing these issues?

Side note - Both of the front hub assemblies as well as the both of the front shock and strut assemblies have recently been replaced. The front differential fluid was also recently replaced.
 

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2006 gmc envoy_slt
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Have you changed your brakes recently? My envoy makes a grinding noise when making sharp turns in 2WD (haven't check in 4WD yet) and I've been told it's the rotors because mine are quite rusted.

Just something to think about.
 

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2003 chevy trailblazer_ls
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No way the rotors would make a noise while turning, but not while running straight, as they turn with the wheel and are always in the same relative position as the wheel.

I would expect one of three things: Your CV axle joint(s) are starting to show wear and when you turn sharp they are making noise (rather common issue with age and mileage, plus engaging 4X4 adds power transmission through those axles making any wear more noticiable); your actual differential is toast (requiring a major tear down), or you are simply noticing the common "axle wrap" that happens when steering a 4X4 vehicle while on dry pavement with a resulting skidding of a tire, etc. making the noise.

In case you do not have a lot of experience with 4X4 vehicles, they tend to get a condition called "axle wrap" (may be called "bind" etc., by others) when all the wheels are engaged on dry or great traction surfaces. This is normal, especially while steering, as the tires normally turn at different speeds during a turn due to the different turning radius of each tire while traveling in an arc. When the axles lock everything togehter bind or wrap often occurs and noise, feed back through the steering wheel (wants to go straight instead of turn), and a general feel of "dragging" occur.

It is not recommended to lock the axles on dry pavement or very high traction surfaces except under severe conditons (like pulling out of a boat ramp, attempting some hill, etc.). On wet or slippery conditions this is not as noticable as the tires can skid somewhat.

If you have worn or broken parts, that is a different story, and they will have to be replaced. No cure except replacement.
 

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2006 chevy trailblazer_ls
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Discussion Starter · #4 ·
Thank You!

Thank you very much for your input! I didn't notice any play in the passenger side axle when I had it off but I havn't checked the driver side yet. I'll have to check it out. If it is actually the differential could that be the reason it won't go into 4 wheel low?
 

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Discussion Starter · #5 ·
Have you changed your brakes recently? My envoy makes a grinding noise when making sharp turns in 2WD (haven't check in 4WD yet) and I've been told it's the rotors because mine are quite rusted.

Just something to think about.
Thanks, the brakes and rotors are fine. this noise is coming from closer to the differential.
 

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Thank you very much for your input! I didn't notice any play in the passenger side axle when I had it off but I havn't checked the driver side yet. I'll have to check it out. If it is actually the differential could that be the reason it won't go into 4 wheel low?
How or when are you trying to shift into 4-low? Do you realize that the vehicle must be stopped and the transmission in neutral before it will shift?

If it goes into 4x4 at all your front differential is likely not your problem, for low range is selected in the transfer case behind the transmission, not in the front axle.

You may not notice "play" and yet still have bad CV axle joints. They make a lot of noise before any amount of play can be felt. If there is any grease around the boots AT ALL, it is likely time for a change. They are not hard to change. Just nuts and bolts.
 

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Discussion Starter · #7 ·
How or when are you trying to shift into 4-low? Do you realize that the vehicle must be stopped and the transmission in neutral before it will shift?

If it goes into 4x4 at all your front differential is likely not your problem, for low range is selected in the transfer case behind the transmission, not in the front axle.

You may not notice "play" and yet still have bad CV axle joints. They make a lot of noise before any amount of play can be felt. If there is any grease around the boots AT ALL, it is likely time for a change. They are not hard to change. Just nuts and bolts.
I was trying to shift while I was parked right after I replaced the disconnect. I turned the switch to 4 wheel high and after it blinked for a while it went into high.When I tried to shift it into low the light blinked for about a minute but never switched over, then I switched back to 2 wheel and the light blinked for a while then turned off completely. I drove around for a while then put it in park switched from 4 high back to 2 and the light came back on. A while back when I was trying to trouble shoot I plugged in a brand new switch and it did the same thing so I don't think the switch has anything to do with it.
 

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Try it with the vehicle parked and in neutral.

The light blinking is the sign that you are not in the right mode to make the shift. It will not shift into 4-low while in park.

Also, the shift requires movement to complete, i.e., the slides in the transfer case will engage the gears but the vehicle must move forward to finish the process and engage everything. Same for turning it off. It takes a few feet of driving to get everything back to the original gear.

DID you have 4x4 in high or are you just reporting that the light came on on the dash?

Take the vehicle onto a grassy area and SEE if you actually are spinning a front tire.

And, while you are at it, run up to 25 or so and JAM on the brakes hard! That will cause the anti-lock brake pump to cycle and you will feel a horrible feeling in your brake pedal. Keep on pushing, that is normal. Doing so on occaision on slippery surfaces like grass or gravel will cycle the anti-lock system to make sure it is ready to operate when or if you need it in traffic.

After 40 years of working on 4x4 vehicles of all sorts, I am constantly amazed that people NEVER utilize the features of their vehicle on a regular and "slippery" surface like a field or gravel, then they attempt to lock in during a snow or ice storm and cuss the vehicle because it doesn't work. :duh: :dielaugh: The idea is to actually RUN the vehicle in ALL MODES including 4x4 high and low, plus cycle the anti-lock brake system on occaision to make sure that all is lubed up and ready for a true need. I've already pulled the diff cover from many a 4x4 vehicle and found the front gears half rusted into place where they stuck above the oil level in the diff because the person NEVER engaged the 4X4 mode for tens of thousands of miles and years. If ya got it, use it once in a while. Really simple and cheapest fix around!
 

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Discussion Starter · #9 ·
Thank You!

Try it with the vehicle parked and in neutral.

The light blinking is the sign that you are not in the right mode to make the shift. It will not shift into 4-low while in park.

Also, the shift requires movement to complete, i.e., the slides in the transfer case will engage the gears but the vehicle must move forward to finish the process and engage everything. Same for turning it off. It takes a few feet of driving to get everything back to the original gear.

DID you have 4x4 in high or are you just reporting that the light came on on the dash?

Take the vehicle onto a grassy area and SEE if you actually are spinning a front tire.

And, while you are at it, run up to 25 or so and JAM on the brakes hard! That will cause the anti-lock brake pump to cycle and you will feel a horrible feeling in your brake pedal. Keep on pushing, that is normal. Doing so on occaision on slippery surfaces like grass or gravel will cycle the anti-lock system to make sure it is ready to operate when or if you need it in traffic.

After 40 years of working on 4x4 vehicles of all sorts, I am constantly amazed that people NEVER utilize the features of their vehicle on a regular and "slippery" surface like a field or gravel, then they attempt to lock in during a snow or ice storm and cuss the vehicle because it doesn't work. :duh: :dielaugh: The idea is to actually RUN the vehicle in ALL MODES including 4x4 high and low, plus cycle the anti-lock brake system on occaision to make sure that all is lubed up and ready for a true need. I've already pulled the diff cover from many a 4x4 vehicle and found the front gears half rusted into place where they stuck above the oil level in the diff because the person NEVER engaged the 4X4 mode for tens of thousands of miles and years. If ya got it, use it once in a while. Really simple and cheapest fix around!
Sorry for taking so long to reply, I couldn't find my email with the link to this site. When I said I got the 4 wheel high to engage the light on the switch lit and stayed solid and all 4 wheels spun ( I had all 4 wheels off of the ground). I was not aware that the car had to be in neutral to engage 4X4 low. I will try all of your suggestions and then report back. Thank you very much for all of your input, you are very helpful as well as insightful.

You said about the "horrible feeling" in the break pedal. When I had the gar jacked up in 4X4 high I pressed on the brakes and it kind of made a grinding sound and it felt like the brakes were having a hard time catching the rotors. I that the feeling you're referring to?
Thanks Again!!
 

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Perhaps, but beware of running a vehicle on jack stands! The drive train is expected to be under pressure and you might find yourself snapping an axle or u-joint from the rather sudden application of power or parts stopping too quickly.

Get that thing on the ground -- best on grass or dirt -- and try your tests again.
 
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